Situated where an evergreen forest overlies the Canadian Shield, the Boreal Shield is the largest of Canada’s terrestrial ecozones. This natural region — popularly known as “shield country” — extends 3,800 kilometres from Saskatchewan to Newfoundland and Labrador. It covers 1.8 million square kilometres and encompasses almost 20 percent of Canada’s landmass; its myriad rivers and lakes account for 22 percent of Canada’s freshwater surface area. The Boreal Shield’s rich supply of minerals and lumber plays a major role in fueling the economy of the “heartland” of southern Ontario and Quebec. Its bare rock, thin soils, and muskeg have restricted development to resource exploitation. Some major communities — Chicoutimi-Jonquière, Sudbury, Elliot Lake, and Thunder Bay — have successfully diversified their economic base, while other one-industry centres have experienced significant declines in population and primary-resource activity. Although less than 10 percent of Canadians reside here, the Boreal Shield’s beauty attracts outdoor enthusiasts from urban centres in the south.